Brake unit for the warp beam of weaving looms

ABSTRACT

The brake unit for the warp beam of weaving looms comprises a pair of supporting levers for the warp beam, which supporting levers are provided each one with a supporting member, in the form of a brake shoe, for the shaft of the warp beam. Above said supporting levers there is provided a pair of corresponding braking levers, which are also provided each one with a brake shoe acting from above onto the warp beam shaft portion. A tie rod connects each supporting lever with the corresponding braking lever.

United States Patent Gardella Mar. 26, 1974 [54] BRAKE UNIT FOR THE WARP BEAM ()F 1,619,039 3/1927 Richards 188/75 WEAVING LOOMS FOREIGN PATENTS 0R APPLICATIONS [76] Invent Gard||a, 24 Via A] 404,045 1/1934 Great Britain 139/100 p (11 Santa Chara, Genoayltaly 681,004 10/1952 Great Britain Filed: June 1972 603,575 4/1960 ltaly 139/100 PP N04 261,959 Primary ExaminerJames Kee Chi Attorney, Agent, or Firm-Larson, Taylor and Hinds [30] Foreign Application Priority Data June 19, 1971 Italy 12759/71 [57] ABSTRACT 52 US. Cl 139/100, 139/109, 188/75 The bfake the warppean weavmg Int Cl D03! 49/08 comprlses a pan of supportlng levers for the warp [58] Field of Search 139/100, 109, 97, 99, 1 R; i?" wh1ch t g g g 66/86 188/75 56 49 wlt a support1ng mem er, In t e orm o a ra e shoe, for the shaft of the warp beam. Above sald sup- 56] Referencescited portmg levers there 15 prov1ded a pan of correspond- 1ng brakmg levers, wh1ch are also provided each one I UNITED STATES PATENTS with a brake shoe acting from above onto the warp 2,424,400 7/1947 Kronoff 139./1 R bear'n shaft portion. A tie rod connects each support- 610734 9/1898 Wolf 139/109 ing lever with the corresponding braking lever. 2,623,703 12/1952 Laycock 139/100 X 1,471,997 10/1923 Clark 188/75 X 2 Claims, 2 Drawing Figures BRAKE UNIT FOR THE WARP BEAM OF WEAVING LOOMS BACKGROUND AND SUMMARY OF THE INVENTION The present invention relates a self-controlled brake unit for warp beams of weaving looms.

It is known that, in weaving looms, the revolving of the warp beam, by unwinding of the warp threads, is promoted by the traction as exerted by the same warp threads which are wound, woven into cloth on the cloth taking-up beam. Therefore, the warp beam is mounted freely rotatable, but is suitably'braked in order to guarantee the required stretching of the warp threads. It is also known that the torque being exerted by the warp threads upon the warp beam gradually decreases with the reduction in diameter of the winding formed by the warp threads being wound on said beam, since it is gradually reduced the lever arm (radius) between the axis of rotation of the warp beam and the traction force peripherally and tangentially exerted by the warp threads upon their respective winding upon the beam. Therefore, by decreasing of the diameter of the winding formed by the warp threads on the warp beam also the braking force exerted upon said warp beam must be correspondingly reduced.

To this end, automatically regulated warp beam brakes are known, in which the gradual release of the brakes braking the warp beam is automatically attained through the control of a feeler roller, or a like member, which bears upon the periphery of the winding formed by the warp threads on the beam, and which is therefore responsive to the gradual reduction in diameter of said winding. Because of said feeler device, the known automatically regulated warp beam brakes result to be very complicated and expensive.

The invention has for its object to eliminate the aforementioned feelers and to overcome the drawbacks arising therefrom, and aims at constructing a brake unit which is simple, sturdy and economical in construction, and which guarantees a perfect operation.

The invention is based upon the fact that while the diameter of the winding formed by the warp threads on their respective beam decreases, also the total weight of the warp beam and the warp threads wound thereon decreases. Therefore the invention avails itself of such a decrease in weight for obtaining the automatic regulation of the warp beam braking, that is, to correspondingly reduce the braking of the warp beam.

According to the invention, in weaving looms, the automatically-regulated warp beam braking unit is substantially characterized by the feature that the warp beam is rotatably mounted upon its ends onto two beam-carrying levers extending in a substantially horizontal direction, and fulcrumed on horizontal pivots, these beam-carrying levers being connected to the warp beam braking means through a suitable transmission having a predetermined ratio, and in such a manner that the said braking means will be operated by the sum of the weights of the warp beam and of the warp threads wound thereupon.

In the warp beam braking unit according to the invention, the force operating the warp beam-braking elements is therefore generated and transmitted with a suitable ratio by the sum of the weights of the warp beam and of the warp threads thereupon. Thus, whilethe diameter of the warp thread winding, and thence the weight of said winding, decreases, also the force acting upon the braking elements, and therefore also the braking of the revolving warp beam is automatically reduced to a corresponding extent. The beam-carrying levers according to the invention actually form a pair f0 load-balance levers whose power is constituted by the force resulting from the weight of the warp beam and its winding, while the resistance is constituted by the force acting upon the beam braking elements. This lever pair or load balance, during the operation, comes to be in equilibrium and therefore practically at rest, since it is the force generated by the weights of the warp beam and the warp thread wound thereon that constitutes the actuating force of the warp beam braking elements.

The several members of the automatically regulated warp beam brake unit according to the invention, and particularly the beam-carrying levers and the mounting of the warp beam thereonto, as well as the beambraking elements and the transmission for their connection to the beam-carrying levers can be made in several different constructional manners. Thus, for example, the beam-carrying levers might be levers either of the first, or the second or third order or class. The beam braking means might be constituted by one or more brake shoes or by a braking band. The transmission between the beam-carrying levers and the beambraking member might be constituted by a rod-andlever system. Preferably, according to a characteristic feature of the invention, the ratio of said transmission is variable and adjustable, so as to render it possible of predetermining at will the starting value of the braking of the warp beam, according to the actual requirements.

One preferred embodiment of the automatically regulated warp beam brake unit according to the invention is substantially characterized by the feature that either one of the beam-carrying levers is suspended by means of a link from a braking lever being substantially parallel to its respective beam-carrying lever and being fulcrumed about a horizontally arranged pivot, which braking lever carries itself the beam-braking element, such as a brake shoe, or operates, either directly or indirectly, the said braking element, such as a braking band.

The means supporting the warp beam onto the beamcarrying levers can be made in any desired manner and for example consist of suitable bearings. Preferably however, according to one particularly advantageous embodiment of the invention, the warp beam has at both ends a brake drum, by means of which it rotatably bears upon a braking shoe having the shape of a circular sector and which is fastened, and preferably hinged to its respective beam-carrying lever, while on said drum another brakingshoe, having the shape of a circular sector, is pressed from above, and is fastened, and

preferably pivotally mounted onto the beam-braking lever from which the beam-carrying lever is depending. In this case, the warp beam is therefore mounted on both ends directly between two braking shoes having the shape of a circular sector, a lower shoe, carried by the beam-carrying lever, or load balance, and the other, or upper shoe, carried by its respective braking lever, these two levers being connected to one another in such a manner that the braking shoes tend to close upon the interposed warp beam brake drum with a force corresponding to the sum of the weights of said beam and of the warp threads wound thereon.

In this latter case, and according to one further characteristic feature of the invention, in order to prevent the warp beam from being axially shifted, the two braking shoes are engaged in a groove peripherally formed in their respective brake drum.

BRIEF DESCRIPTION OF THE DRAWING These and other characteristic features of the invention and the advantages arising therefrom will be apparent from the following specification of one preferred embodiment shown in the accompanying drawing, in which:

FIG. 1 shows in side elevation, with parts in section, the warp beam of a weaving loom, which is provided with a brake unit according to the invention.

FIG. 2 is a plan view of one end of the warp beam with parts in section on line IIlI of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the drawing, 1 denotes the warp beam ofa weaving loom, and 101 denotes one of the end flanges of said beam between which the winding A of the warp threads F is formed. At either end of the beam 1, outwardly of its respective flange 101, the warp beam 1 has a brake drum 2 rigidly fastened to said beam. The said drum 2 has a peripheral groove for example formed by two small flanges or rims 102.

At either end of the warp beam 1, under its respective drum 2, a beam-supporting lever 3 is provided, which is arranged in a substantially horizontal position and which is fulcrumed on a horizontal pivot 4 fastened to the weaving loom frame. Onto each beamsupporting lever 3 a braking shoe 7 having the shape of a circular sector is mounted on a pivot 6. The warp beam 1 rotatably bears with its drums 2 upon the braking shoes 7 of the beam-supporting levers 3.

To each beam-supporting lever 3 a beam-braking lever 8 is associated, which is substantially horizontally disposed above the respective drum 2 of beam 1, and is mounted onto the weaving loom frame by being fulcrumed onto a horizontal pivot pin 9. Each beamcarrying lever 3 and its respective beam-braking lever 8 preferably are in the same vertical plane, and their pivot pins 4 and 9 are parallel to one another. A braking shoe 11, having the shape of a circular sector and bearing from above upon its respective drum 2 of the warp beam, is mounted on a pivot pin 10, onto each braking lever.

Each beam-supporting lever 3 is suspended from its respective braking lever 8 by means of a substantially vertical tie rod 12 which is linked to said levers 3 and 8. Both the beam-supporting lever 3 and the beambraking lever 8 have a longitudinal row of holes 103, respectively 108, in which the suspension rod 12 can be linked, thus rendering it possible to adjust the said rod 12 along said levers 3, 8.

In the aforementioned conditions, the warp beam 1 comes to be rotatably mounted at either end, through its respective brake drums 2, between a lower braking shoe 7, pivotally mounted onto the beam-supporting lever 3, and an upper braking shoe 11 pivotally mounted onto the beam-braking lever 8. Both braking shoes 7 and 11 having the shape of a circular sector are engaged in the peripheral groove of their respective drums 2, between the projecting rims or flanges 102 of said drums, so that the same prevent any axial movement of the beam 1. The sum of the weights of the warp beam 1 and of the'warp threads F forming thereupon the winding A bears through the lower braking shoes 7 upon the beam-supporting levers 3 and therefore tends to rock the said levers downwardly, about their co-axial pivot pins 4. The beam-supporting levers 3, by being linked by means of the rods 12 to their respective beam-braking levers 8, tend, in turn, to rock these latter levers downwardly about their co-axial pivot pins 9. The lever arm between the suspension rod 12 and the fulcrum 9 of the braking lever 8 is shorter than the lever arm between the said rod 12 and the fulcrum 4 of the beam-carrying lever 3. On the contrary, the lever arm between the pivot 10, by means of which the upper braking shoe 11 is pivotally mounted onto the beambraking lever 8, and the fulcrum 9 of said lever is longer than the lever arm between the hinge pivot 6, of the lower braking shoe 7 onto the supporting lever 3, and the fulcrum 4 of said lever. Therefore, the two pairs of shoes 7 and 11 are pressed upon the respective drums 2 of the warp beam 1 with a force being generated by the total weight of said beam 1 and of the warp threads F forming thereon the winding A.

The ratio between this weight and the force with which the braking shoes 7, 11 are pressed against the brake drum 2 is determined by the position of the suspension rod 12 on the two levers 3, 8 and can be varied by shifting the rod 12 along the row of linking holes 103 and 108.

From the foregoing, it is apparent that the braking of the warp beam 1 depends upon the combined weights of said beam 1 and the warp threads winding A. While the diameter of said winding is decreasing, also its weight, and thence the total weight bearing upon the beam-supporting levers 3, will decrease to a corresponding extent. Therefore the force with which the braking shoes 7 and 11 are pressed upon their respective drums 2 will be automatically reduced, so that also the braking of the warp beam 1 comes to be automatically reduced as required by the reduction in diameter of the winding A of the warp threads F. Notwithstanding this variation, the beam-supporting levers 3 and the beam-braking levers 8 will remain practically stationary during the operation of the loom, since they constitute a balances system in which only the magnitude of the force acting thereupon varies.

At the starting of a weaving operation, in order to render easy the mounting of the warp beam 1 with the whole winding of the warp threads F, which is very heavy, at the free end of either beam-supporting lever 3 an auxiliary device of the jack or the winch type is provided, by means of which the beam-supporting levers 3 can be easily lifted up together with the warp beam 1 bearing upon their shoes 7. This lifting device might be constructed in many different manners. In the embodiment as shown, the same is constituted by a vertical nut screw 13 and which is rotatably, but not slidably, mounted in a vertical supporting sleeve 14 secured to the loom frame 5. The nut screw 13 can be rotated by means of a handwheel l5 and in said screw is engaged a vertical screw spindle 16 which is slidably but not rotatably mounted in the sleeve 14. At the lower end of the screw spindle 16 a flexible tie member is linked, which is, for example, constituted by a chain l7 and is provided with means 18 for connecting it to its respective beam-supporting lever 3.

When the warp beam 1 is to be mounted, the suspension rods 12 are removed, so that the beam-supporting levers 3 swing freely downwardly about their pivot pins 4 and fall, for example, in their lower position, shown by dot-and-dash lines in FIG. 1. On the contrary, the beam-braking levers 8 are swung up to a position, in which the same are connected to the weaving loom frame 5 by means of tie rods 19, which might even be constituted by the same suspension rods 12, as shown by dot-and-dash lines in FIG. 1. The warp beam 1 is mounted by fitting its drums 3 upon the braking shoes 7 of the beam-supporting levers 3, while in their downward position, and these latter levers are connected to the lower ends of the chains 17. Whereupon, by rotating the nut screws 13 by means of the handwheels 15, the threaded spindles 16 are driven upwards so as to pull up the chains 17 and cause the beam-carrying levers 3 to be upwardly lifted, together with the warp beam 1, up to the position that this beam must assume during the weaving. The beam-braking levers 8 are then untied from the loom frame 5, and these levers will swing down and cause their braking shoes 11 to bear upon the drums 2 of beam 1. Thereafter, the suspension links 12 connecting the beam-carrying levers 3 to their respective beam-braking levers 8, are assembled. Finally, by driving the nut screws 13 in the opposite direction, by means of the handwheels 15, the screws 16 are lowered down until the beam-carrying levers 3 will be suspended from their respective beambraking lever 8 by means of the links 12. This operational condition of the brake unit is shown in FIG. 1, in which it might be observed that, in operative condition, the chains 17 of the lifting devices 13, 14 are slack and therefore will not exert any traction upon the beamsupporting levers 3, but will leave the same quite unrestrained.

Of course, the invention is not limited to the shown and described embodiment, but can be widely varied and modified, without departing from the leading principle as afore-specified and as claimed hereinafter;

I claim:

1. A brake unit for the warp beam of weaving looms, comprising: a pair of warp beam supporting levers, arranged each one at a respective side of the loom frame, said supporting levers being fulcrumed at one end thereof to the loom frame about a common horizontal axis, and being provided each one with a supporting member for rotatably supporting the shaft portion of the warp beam which projects out of each end of the warp beam itself; a pair of braking levers arranged each one at a respective side of the loom frame, substantially above a corresponding supporting lever and above a corresponding shaft portion of the warp beam, said braking levers being fulcrumed at one end thereof to the loom frame about a common horizontal axis, each braking lever being provided with a braking element which acts from above onto the corresponding shaft portion of the warp beam; connecting means for operatively connecting in a releasable manner each one of the supporting levers to the corresponding braking lever, said connecting means being shiftable in an adjustable manner along the supporting levers and the braking levers, said connecting means consisting of a tie rod which is hingedly connected at one end to the supporting lever at a point beyond the supporting member in the direction of the free end of the supporting lever, while at its other end it is hingedly connected to the braking lever at a point between the fulcrum of said braking lever and the braking element, the lever arm extending between the point of connection of the connecting means of the braking lever and the fulcrum of said braking lever being shorter than the lever arm between the point of connection of the. connecting means on the supporting lever and the fulcrum of said supporting lever, the lever arm existing between the fulcrum of the braking lever and the braking element thereon being longer than the lever arm between the fulcrum of the supporting lever and the supporting member thereon; the shaft portion of said warp beam being constructed as a brake drum, and both the 'supporting members of the supporting levers and the braking elements of the braking levers being constructed as brake shoes capable of acting on said drum; means for locking the braking levers in a suspended position, whenever the connection means between said braking levers and the corresponding supporting levers are released, while the supporting levers are free to swing in a downward direction, to a swung down position where the warp beam can be discharged from or loaded onto the supporting members on the supporting levers; and auxiliary lifting means for lifting the supporting levers loaded with the warpbeam from the swung down position to the position at which the said supporting levers can be again connected to the braking levers by the connecting means.

2. A brake unit according to claim 1, wherein the auxiliary lifting means comprise:

a. a vertically directed lead nut which is rotatably mounted but not axially shiftable, on the loom frame above the free endof each supporting lever;

b. a screw which is guided axially shiftable but not rotatable through said nut;

c. a flexible tie member secured at the lower end of the screw and provided with suitable means adapted to engage in a releasable manner the free end of the supporting lever. 

1. A brake unit for the warp beam of weaving looms, comprising: a pair of warp beam supporting levers, arranged each one at a respective side of the loom frame, said supporting levers being fulcrumed at one end thereof to the loom frame about a common horizontal axis, and being provided each one with a supporting member for rotatably supporting the shaft portion of the warp beam which projects out of each end of the warp beam itself; a pair of braking levers arranged each one at a respective side of the loom frame, substantially above a corresponding supporting lever and above a corresponding shaft portion of the warp beam, said braking levers being fulcrumed at one end thereof to the loom frame about a common horizontal axis, each braking lever being provided with a braking element which acts from above onto the corresponding shaft portion of the warp beam; connecting means for operatively connecting in a releasable manner each one of the supporting levers to the corresponding braking lever, said connecting means being shiftable in an adjustable manner along the supporting levers and the braking levers, said connecting means consisting of a tie rod which is hingedly connected at one end to the supporting lever at a point beyond the supporting member in the direction of the free end of the supporting lever, while at its other end it is hingedly connected to the braking lever at a point between the fulcrum of said braking lever and the braking element, the lever arm extending between the point of connection of the connecting means of the braking lever and the fulcrum of said braking lever being shorter than the lever arm between the point of connection of the connecting means on the supporting lever and the fulcrum of said supporting lever, the lever arm existing between the fulcrum of the braking lever and the braking element thereon being longer than the lever arm between the fulcrum of the supporting lever and the supporting member thereon; the shaft portion of said warp beam being constructed as a brake drum, and both the supporting members of the supporting levers and the braking elements of the braking levers being constructed as brake shoes capable of acting on said drum; means for locking the braking levers in a suspended position, whenever the connection means between said braking levers and the corresponding supporting levers are released, while the supporting levers are free to swing in a downward direction, to a swung down position where the warp beam can be discharged from or loaded onto the supporting members on the supporting levers; and auxiliary lifting means for lifting the supporting levers loaded with the warp beam from the swung down position to the position at which the said supporting levers can be again connected to the braking levers by the connecting means.
 2. A brake unit according to claim 1, wherein the auxiliary lifting means comprise: a. a vertically directed lead nut which is rotatably mounted but not axially shiftable, on the loom frame above the free end of each supporting lever; b. a screw which is guided axially shiftable but not rotatable through said nut; c. a flexible tie member secured at the lower end of the screw and provided with suitable means adapted to engage in a releasable manner the free end of the supportIng lever. 